This got the letter authors thinking. As chocolate is often combined with milk, could it be the amount of milk/milk products consumed per head that fuels Nobel Prize success?

They looked at the 2007 data from the Food and Agriculture Organization on per capita milk consumption in 22 countries as well as the information provided by the author of the chocolate theory, and found a significant association.

Sweden has the most Nobel laureates per 10 million of its population (33). Although, it hosts the Nobel committee, which some might argue could introduce an element of bias; it also consumes the most milk per head of the population, getting through 340kg every year.

And Switzerland, which knocks back 300kg of the white stuff every year, has a Nobel haul of similar proportions (32).

At the other end of the scale, China has the lowest number of Nobel laureates in its population. But it also has the lowest milk consumption of the countries studied—at around 25kg a year.

There does seem to be a ceiling effect, however, note the authors, with no discernible impact beyond an annual per capita consumption of 350kg, as Finland's Nobel haul seems to attest.

Is milk consumption therefore simply a reflection of a strong educational system, or do Nobel Prize winners celebrate by drinking it, query the authors?

But there is a plausible biological explanation for the link: milk is rich in vitamin D, and this may boost brain power, the evidence suggests.

"So to improve your chances of winning Nobel prizes you should not only eat more chocolate but perhaps drink milk too: or strive for synergy with hot chocolate," conclude the authors, who highlight their conflicts of interest, which include a tendency to take milk with cereal and coffee, and to eat chocolate whenever the opportunity arises.